Variable Connectivity Model for Determination of pKa Values for Selected Organic Acids
Matevž Pompe*,1 and Milan Randić2
1 Faculty of Chemistry and Chemical Technology, University of
Ljubljana, Aškerčeva 5, 1000 Ljubljana, Slovenia,
Fax: ++386 1 2419 220
2 National Chemical Institute, Hajdrihova 19, 1000 Ljubljana; 3225
Kingman Rd. Ames, IA 50014, USA;
E-mail: matevz.pompe@guest.arnes.si
Abstract
A variable anti-connectivity topological index was optimized for the modeling of
pKa values. The variable anti-connectivity index of order one showed
superior modeling capabilities compared to ordinary variable connectivity index
of the same order because it is capable to account for the combination of
positive and negative contributions for the molecular descriptor in structure-property-relationship.
Additionally we examined functional dependence of individual bond contributions
on modeling property by varying also the exponent appearing in connectivity
index. Such variation did not make significant improvements of the calculated
results.
Keywords: Anti-connectivity, variable connectivity index, pKa, prediction.